A fuel cell has been proposed as a clean, efficient and environmentally responsible power source for various applications. Fuel cells are electrochemical devices which combine a fuel such as hydrogen and an oxidant such as oxygen to produce electricity. The oxygen is typically supplied by an air stream. The hydrogen and oxygen combine to result in the formation of water.
Individual fuel cells can be stacked together in series to form a fuel cell stack capable of supplying a quantity of electricity sufficient to power an electric vehicle. The fuel cell stack has been identified as a potential alternative for a traditional internal-combustion engine used in modern vehicles.
Known fuel cell systems have used a hydrogen sensor in an exhaust of the fuel cell stack to supervise a hydrogen concentration emitted to the environment. However, in typical fuel cell systems, not enough hydrogen is present in the exhaust during normal operation to test the hydrogen sensor. Also, with conventional fuel cell system mechanizations, it has previously not been possible to generate hydrogen exhaust test pulses for diagnosing the hydrogen sensor.
There is a continuing need for a system and method to enable hydrogen sensor diagnostics in a fuel cell system. Desirably, the system and method provide a hydrogen test pulse for testing the hydrogen sensor of the fuel cell system.